More than 130 HIV-positive South African women are seeking asylum in Canada after attending the Toronto Aids conference last month, apparently claiming that they cannot get adequate treatment at home.

The case draws more attention to the deepening controversy over whether President Thabo Mbeki's government is providing appropriate medical treatment to millions of people with Aids and HIV.

The women have not yet spoken about why they do not want to return home. But it is thought that they will argue that the stigma and discrimination they face as HIV-positive people in South Africa, not to mention the problems in securing proper medical treatment, amount to persecution.

People with HIV in South Africa have faced an uphill battle to gain access to anti-retroviral drugs, which have only been provided since 2002, when the country's Treatment Action Campaign brought a legal challenge to force the government of President Thabo Mbeki to offer the drugs.

The government has more than 140,000 people on the drugs, the largest such programme in the world. A further 80,000 South Africans pay for the drugs themselves at a cost of about £150 a year.

But such figures are dwarfed by the 700,000 South Africans in urgent need of anti-retroviral drugs. Critics say people are dying because the government has delayed making the drugs available.

"We are aware of a group of about 140 women seeking asylum in Canada," South Africa's foreign affairs spokesman, Ronnie Momoepa, told the Guardian yesterday. He said said the high commissioner in Canada, Eddie Nkomo, was in touch with the Canadian authorities to ascertain among other things the nationalities of the individuals.

The South Africans applying for asylum in Canada are part of a 150-strong group with HIV who have refused to leave Canada after the conference. They are seeking refugee status to live there permanently, the Toronto Sun newspaper reported. Others seeking asylum are from El Salvador, Eritrea, Uganda and Zimbabwe.

Canadian officials said it might take a year for officials to rule on the cases. About one in two applications for asylum in Canada is successful.

The Eritrean Aids activist Amanuel Tesfamichael, 32, spoke of his decision to seek asylum. "I was only allowed to leave my homeland for 10 days. It feels so good to be free," he told the Toronto Sun.

Mr Tesfamichael is the founder of Eritrea's 6,000-member association for people living with Aids. He said he was allowed to travel to Canada on condition that he surrender his passport to two government minders.

Last week the South African Medical Research Council said more than 330,000 South Africans had died of Aids-related ailments in the past 12 months. About 947 South Africans die from Aids-related illnesses every day, while 1,443 become newly infected with HIV, according to a separate study also released last week.

At the Toronto conference, the UN envoy on Aids, Stephen Lewis, made a scathing attack on the South African government, calling it "obtuse, dilatory and negligent about rolling out [anti-Aids] treatment". Mr Lewis attacked the Mbeki government's policies as "wrong, immoral and indefensible". He called the government's theories "more worthy of a lunatic fringe than of a concerned and compassionate state".

Background: Aids crisis

With some 5.5 million people who are HIV positive, South Africa has the second largest number in the world after India. Yet its government only started providing anti-retroviral drugs four years ago.

President Thabo Mbeki has expressed doubts as to whether HIV causes Aids, while his health minister, Manto Tshabalala-Msimang, has said she had more faith in lemon, beetroot and garlic to treat Aids. The country's stand at the Toronto conference included garlic, beetroot, and potatoes. Some boxes of anti-retroviral drugs were added, but these were apparently borrowed.

Mark Heywood, of the Aids Law Project at the University of the Witwatersrand and the Treatment Action Campaign said South Africa was only treating 17% of its Aids sufferers. It has 200,000 people on anti-retroviral drugs for Aids, of whom 130,000 are treated in the public sector. But about 700,000 people with HIV need the drugs and will soon die without them.